Asbestos fibers in mine roof coatings



'the visibility of the surroundings.

ASBESTOS FIBERS 1N MINE ROOF coaruscs I William C. Streib, North Plainfield, N1, and James G.

Rowe HI Houston, Tera, assig'nors to Jolms-Mnnville Cforpgoration, New York, N.Y., a corporation of New No Drawing. Filed Oct. 11,1957, Ser. No. 689,479

'9 Claims. (Cl. 169-2). 1

This invention relates to theuse of asbestos floats fibers and mixtures of these with limestone {or mine roof Also, theasbestos reduces the drippings of the asphalt through the dust layer .which had previously resulted in 1 qmany undesirable protrusions from the mine roof. The

color life of the coating ishigh since the asbestos floats or fibers donot have a tendency to become embedded t in and coated by the asphalt. 1

Under some conditions, it may bedesrable for economic reasons to spray a mixture of asbestos'fi-bers and limestone dust onto a mine root and walls as the coating.

As with the absestos floats and fibers alone, this may be applied to amine roof with or without the asphalt coatcoatings. Although disclosed in connection with asbestos fibers, other mineral fibers such as fibrous talc, anthophyllite, rock wool, wollastonite and other abestiform materials may be used.

During the initial cutting of amine it isv necessary to provide themine roof and walls with a'coating of rock dust to diminish the danger at explosion and-*fo increase visibility. In this invention, asbestos floats or fibers are used to coat the mine roof and walls'so that the asbestos may adulterate the coal dust below the explosion point. As used inthe specification and claims,"

the term, asbestos fibers, is meant to include both asbestos fibers and asbestos floats.

Also, it has been customary in some localities to cover mine roofs withasphalt andother materialsto reduce spalling, cracking and rock fall. The coated roofs are then dusted with ground or particulate limestone or other the fire hazard, and-to improve visibility. Considerable difliculty has been encounteredwith these processes in ing. Unusual and advantageous results have been obtained' with a mixture of asbestos fibers and 75%] particulate limestone byvvolume. A mixture in the above proportion is prepared and sprayed on the mine roof and walls with customary spraying apparatus. The addition of the asbestos reduces the dust in the atmosphere dur'-' ing spraying and also removes the necessity of applying a second coat.

The use of asbestos fibers or floats either alone or'in mixtures with groundor particulate limestone has produced coatings .for mine roofs and walls which are far superior to priorcoatings. The asbestos fibers orfloats remain in the applied condition so that after many months of application the asbestos is more readily dislodged than fother coatings which have a tendency to cake. This is I types of ground rock to 'help set the coating, to lessen that! (l) the dust particles have a tendency tobecome '1 imbedded in andcoated by the asphalt; (2).the dust particles vallow the asphalt to drip through, thus forming;

protrusions from the mine roofs which allow moisture toconcentrate incer-tain areas and to'result in annoying drippings; and, (3) the dust particles do not readilyv adhere to the coating and require repeated application. I

This invention solves these problems :by using asbestos floats or fibers for coating-the mine roof. The asbestos fiber, either alone or mixed with ground or particulate limestone, is applied to the asphaltcoatin'g and the walls by spraying. It is a primary object of this invention to provide a v method for coating mine roofs and walls which reducesthe danger of explosion and increases visibility.

' Thus, since the asbestos retains its original condition, it

highly advantageous since the coal dust prevailing in the mine, is adulterated below the explosion point by the gradual dissipation of the coating from the walls andv roof into-the atmosphere as the result of air turbulence.

can provide this highly desired result for a much longer time.

" Having thus described the invention in ratheriull detaiL'it will be understood that these details need not a be strictly adhered to and that various changes and medi fications may suggest themselves to one skilled in the ar-t, all falling within the scope of the invention as described by the subjoined claims. 40 Y I What we claim is:' 1. The method of treating a mine roof and walls to.

'adulterate the coal dust below the explosion point and H to afford proper illumination which comprises coating the mine root and walls with a layer of asbestos fibers.

The invention will be more fully understood and fur-- ther objects and advantages thereof will become apparent whenreference is made to the rfollowing detailed description of a preferred embodiment of the invention.

As a coal mine is evacuated, it is necessary to continually coat the mine roof and walls so as to adulterate the coal dust below the explosion point and to increase In locations where the geographical formation and the condition of the mine is favorable, asbestos floats or fibers alone are used to provide the desired coating. In this process, mixes. of 100% asbestos floats or fibers are sprayed in the usual manner so that the asbestos adheres to the mine roof and walls. After application, the asbestos remains in a flaky condition so as to adulterate the coal dust below the explosion point by the gradual dissipation of the asbestos from the roof and walls as the result of air turbulence.

Where the geographical formation and the condition 'of the mine is not ideal, the mine roof is coated with asphalt to reduce spalling, cracking and rock fall. To lessen the fire hazard, to set the coating and to improve the visibility, the asphalt coating is then sprayed with 2. The'method of treating a mine roof and walls to;

adulterate the prevailing coal dust below the explosion point and to afford proper illumination which comprises spraying a mixture of 100% asbestos fibers on said roof and said walls. v

3. The methodof treating a mine roof-and walls to adulterate the prevailing coal dust below the explosion I point and to afford proper illumination which comprises coating the mine roof with asphalt to reduce spelling,

cracking and rock fall, and coating said niineroof and said walls with a mixture of asbestos fibers. v

4. The method of treating a mine roof and walls to .adulterate the prevailing coal dust below the explosion point and to atford proper illumination which comprises coating the mine roof with asphalt to reduce sp alling, cracking and rock fall, and spraying a mixture of 100%" asbestos fibers on said asphalt coating and said walls. -5. The method of treating a mine roof and walls to adulterate the prevailing coal dust below the explosion point and to afford proper illumination which comprises coating the mine roof with asphalt to reduce spalling, cracking and rock fall. and coating said mine roof and saidwalls with a mixture of asbestos fibers and particulate limestone, said mixture comprising at least about I 25% by volume of asbestos fibers. w 6. The method of treating a mine roof and walls to adulterate the prevailing coal dust below the explosion V point and to atlord proper ili::=mination which comprises 3,055,4 45 Patented Sept. 25, I962;

M -er coating the mine roof with asphalt to red uce spalling,

cracking and rock fall, and spraying a mixture of asbes tos fibers and particulate limestone on said asphalt coatthe mine roof and walls with a material comprising inorganic mineral-fibers in the amount/0f at least about 25% by volume.

v 17. The-method of treating a mine roof and walls to adulterate the coal dust below the explosion point and.

m afim-d proper illumination which comprises coming 4' ture comprising at least about 25%--by volume of inor- 8. The method of treating 'a' mine roof and walls to adulterate'the coal dust below the explosion point and to afford proper illuminationwhich comprises coating the mine roof and walls with inorganic mineral fibers. 9. The method of treating a mine roof and walls to 1 adulterate the coal dust below the explosion point-mud to afford proper illumination which comprises coating" the mine roof and walls with a mixture comprising inorganic mineral fibers and particulate limestone, said mixganic mineral fibers. 1

References Cited in the file of this patent Proceedings of the Engineers Society of Western 

1. THE METHOD OF TREATING A MINE ROOF AND WALLS TO ADULTERATE THE COAL DUST BELOW THE EXPLOSION POINT AND TO AFFORD PROPER ILLUMINATION WHICH COMPRISES COATING THE MINE ROOF AND WALLS WITH A LAYER OF ASBESTOS FIBERS. 